This paper is part of the Proceedings of the 12th International Conference on Retinal Proteins held at Awaji Island, Hyogo, Japan on 4–8 June 2006.
Photoreceptive Systems in Ascidians†
Article first published online: 27 FEB 2007
Photochemistry and Photobiology
Volume 83, Issue 2, pages 248–252, March/April 2007
How to Cite
Kusakabe, T. and Tsuda, M. (2007), Photoreceptive Systems in Ascidians. Photochemistry and Photobiology, 83: 248–252. doi: 10.1562/2006-07-11-IR-965
- Issue published online: 27 FEB 2007
- Article first published online: 27 FEB 2007
- Received 11 July 2006; accepted 23 August 2006; published online 29 August 2006
The brain vesicle of the tadpole larva of ascidians, simple basal chordates, contains an eye-spot (ocellus), which is responsible for the photic swimming behavior. Ascidian adults also exhibit several types of light-responsive behaviors. Molecular phylogenetic studies have suggested that ascidians are the closest living relatives of vertebrates, and therefore, understanding the photoreceptive systems in ascidians is a key to uncover the origin and evolution of the vertebrate eyes. The ocellus of the ascidian larva has ciliary photoreceptors resembling those of the retina and pineal eye of vertebrates. Recent studies have indicated that the ascidian larva has phototransduction and visual cycle systems similar to those of vertebrate eyes. Comparative studies on photoreceptor systems between ascidians and vertebrates provide us clues to reconstructing the evolutionary pathway leading to the lateral and median eyes of vertebrates.